1. Technical Field
The present invention relates to a target recognition system to recognize one or more recognition targets, and a recognition method executed by the target recognition system.
2. Related Art
At present, vehicle-mounted recognition systems that recognize obstacles based on a captured image of the area ahead of the vehicle are widely used for driver support systems such as adaptive cruise control (ACC), to reduce the burden on the driver.
The driver support systems provide various functions, including a brake-control-and-alert function that alerts the driver to take corrective action to avoid a collision or reduce the impact of the collision, a driving speed adjustment function to maintain a safe minimum distance between vehicles, and a stray prevention function to prevent the vehicle from straying into another lane.
In JP-2008-146549-A, a driver support system that attempts to alleviate the burden on the driver of the vehicle by recognizing targets based on the image of area ahead of the vehicle captured by the imaging devices is disclosed. In order to recognize the targets shown in the captured image, the color and spatial frequency of the target are detected from the captured image. By integrating the detected spatial frequency for generating a distribution of the spatial frequency, the characteristics of the spatial frequency are detected. Then, the recognition target is recognized by comparing the detected target color and spatial frequency characteristics with predetermined target color and spatial frequency characteristics.
In order to implement the driver support system, it is necessary to recognize obstacles in the way of the vehicle accurately. However, in the above-described driver support system, the captured image may contain an image of an object similar to the recognition target. The system performs the same predetermined recognition processing to compare color and spatial frequency features of the image of the similar object with those of the recognition targets. As a result, the image of the object similar to the recognition target may be falsely recognized as the image of the recognition target, which makes it difficult to for the driver support system to function as intended.